During her elementary school years, Sayaka Saeki took great pride in being the perfect child. She excelled in her studies, took part in many after-school activities, and always displayed proper manners, believing that her life was unfolding exactly as she intended. But when a girl from her swim class confessed romantic feelings to her, Sayaka came to understand that emotions can overturn even the most rational and clear-cut thinking.
At the start of middle school, wanting to collaborate with her classmates instead of vying with them, Sayaka adopted a new attitude and became friends with her upperclassman Chie Yuzuki. As their gentle friendship deepened, Yuzuki admitted her love to Sayaka. In an effort to comprehend what love truly meant, Sayaka returned her affections. Even though she put her academic dedication on the back burner, the relationship eventually fell apart, leaving Sayaka wounded and bitter.
Vowing to never again allow her emotions to dominate her existence, Sayaka resolved to reclaim her self-reliance upon entering high school. However, when she notices class representative Touko Nanami, Sayaka is forced to confront the conflict between embracing her genuine identity and adhering to her rational approach to life.